The invention is directed to a thread splicing arrangement having a splicing head with a splicing channel which is open at both ends and on one side thereof, for the receipt of thread to be spliced. Discharging into such a splicing channel are two pressurized gas channels whose outlets are arranged symmetrically with respect to the middle of the splicing channel. Such a thread splicing arrangement has a lid for closing the open side of the splicing channel as well as a holding means outside the splicing channel and close to the open ends thereof, for clamping the two thread ends being spliced together with a cutting arrangement for cutting the free thread ends.
In a known thread splicing arrangement of this type (DE PS 3536580), a pressure gas channel discharges in the center of the base of a splicing channel and has an axis perpendicular to the longitudinal axis of the channel. A holding means is so provided that after the splicing of the threads in the splicing chamber, they are located near the lid thereof. During the splicing step the pressurized gas stream forces the threads against the lid and then divides itself into two partial streams which discharge from both ends of the channel thereby entangling the threads with each other. Instead of just a single central gas outlet opening in the middle of the splicing channel base, two or more openings may be provided symmetrically with respect to the center of the splicing channel. Since during splicing a free, that is, unclamped thread end is permitted, a very simple mode of construction is possible. For example, the cutting step can be simultaneous with the closing of the lid.
In another known type of thread splicing arrangement (DE PS 3040661) a pair of pressurized gas outlets are located above and below the transverse symmetrical plane of the splicing channel as well as to the left and the right of a longitudinal symmetrical plane. Accordingly, one gas stream creates a clockwise air vortex and the other a counter-clockwise air vortex about the inserted threads, thereby effectively splicing tightly twisted yarns and threads. In practice, the ends of both of the inlaid threads are held fast close to the outer ends of the splicing channel. The gas streams running alongside the threads generally take hold of the circumference of the threads.
One air stream for splicing by a further known thread splicing arrangement (DE OS 33 37 847) comprises a vortex chamber in which the inlaid yarn ends are cut and held and are spliced by at least a further air stream. For this purpose there are provided one or more splicing jets transverse to the axis, in the middle area of the vortex chamber; whereas in the area of the front end of the vortex chamber, there is provided at least one preparation jet. This preparation jet can operate either with over-pressurized gas or with a vacuum. The air stream can be given a counter-twisting movement to assist the unspinning of the thread.
In another known thread splicing arrangement (DE OS 38 08 814), there are provided a pair of mutually opposed, slot-shaped air jets whose streams meet just above the thread lying on the base of the splicing chamber. Outside the vortex chamber there are provided two reverse twist jets for thread end preparation. Between these and the vortex chamber there is provided a thread pressing arrangement which holds the threads at both ends.
An object of the present invention is to provide a thread splicing arrangement of the generally described foregoing type which despite the presence of free threads ends achieves a good splicing result for a variety of different thread materials.